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August 1952 E-844 

United States Department of Agriculture 

Agricultural Research Administration 

Bureau of Entomology and Plant Quarantine 


By Ross H. Arnett, Jr. 
Division of Insect Detection and Identification 

That the family Lyctidae, the false powder-post beetles, is of 
economic importance is indicated by the numerous times these small 
beetles are encountered in various manufactured goods, such as ax and 
hammer handles, baskets, and furniture, as well as in buildings and in 
herbs and roots. 

Recently two species, Lyctus prostomoides Gorham and L. impressa 
Comolli, have come to my attention as intercepted and imported pests. 
Although there is no evidence that they have become established in this 
country, they may have gone unrecognized as " Lyctus sp." Another species 
L. villosa Lesne, was sent in for identification recently, and from the 
data accompanying the specimens, as well as from additional specimens 
in the U. S. National Museum collection, it appears that this species may 
have become established in this country, but has not yet been recorded in 
the literature. Therefore, a few notes on the distinctive appearance of 
these species, their hosts and distribution, may call attention to their 
presence in this country, either in existing collections or in those made 
in the future. 

There is some controversy over the proper generic placing of the first 
two species mentioned above. The current catalog (Lesne _7, pp. 14-16) 
places them in the genus Trogoxylon LeConte (_5, p. 209). The validity of 
the separation of this genus from Lyctus Fabricius (2, p. 502) is question- 
able. LeConte's separation was on the basis of the structure of the 
anterior tibiae (viz., anterior tibia with the outer apical angle not pro- 
longed in Trogoxylon and prolonged in Lyctus) . This character has since 
been shown not to be constant for the species which LeConte included in 
the genus. In the original description of the genus the genotype of 
Trogoxylon was designated as the species Xylotrogus parallelipipedus 
Melsheimer (8, p. 112). This designation gives us a basis for a definition 
of the genus. The group that LeConte considered as constituting this 
genus corresponds roughly to Kraus's (_4, pp. 116-118) group of species of 
Lyctus with confused pubescence and confused or somewhat striate elytral 
punctation. These species may or may not form a natural group but these 

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characters are hardly sufficient for the erection of a separate genus, 
particularly when the other genera placed in this family are so distinct 
from the genus Lyctus in the broad sense. Therefore, I prefer to keep 
the generic name Lyctus in the old sense to include Trogoxylon , at least 
until more comprehensive work is done and it is demonstrated that other 
characters, such as those of the larvae and male genitalia, show that 
further division of Lyctus is necessary. 

The following information should help in the recognition of the three 
species mentioned above and summarizes their distribution. The host 
data are from specimens in the U.S. National Museum collection. 

Lyctus prostomoides Gorham 

Lyctus prostomoides Gorham (J3, p. 212) 

Type locality : El Tumbador, Guatemala. 

Size 2.5-5 mm. Color reddish-brown. Head with a prominent 
double tubercle over the base of the antennae; thorax widest in front, 
lateral margins nearly straight, anterior and posterior angles acute, 
punctures moderately large, dense, deeper than those of elytra; outer 
apical angles of anterior tibiae moderately produced; elytral pubescence 
confused, moderately long and dense, recumbent, fine, yellow in color, 
punctures confused, shallow, moderately dense. 

This species will key to "Section a2" in Kraus's key (4), but will fit 
neither alternative in that couplet because the pronotum is broader than 
long and the pubescence is fine and not bristling and the prosternum is 
not distinctly punctate throughout. 

Hosts: Lacquered tray, wooden crate, dry wood, bamboo, carved 
wood, basket, furniture, stem of Sambucus sp., and dried herbs. 

Distribution and interceptions : Panama: San Lorenzo (Champion); 
Guatemala: San Geronimo, Purula, El Tumbador (Champion); ?Nicaragua: 
Chontales (Janson); Mexico: Cordoba (Knab), Jalisco (Diquet), Guanajuato 
(Salle), Cuernavaca (via Chicago, 111.), Guadalajara (via Nogales, Ariz.), 
"Mexico" (via Brooklyn, N. Y.), "Mexico" (via New York, N.Y.), 
"Mexico" (via Pittsburgh, Pa.), "Reared from elephant carved from 
soft African wood purchased from London dealer in Persian goods" 
(via Rochester, N.Y.). 

Lyctus impressa Comolii 

/Tyctusj7 /Tmpressa]?7 Comolii (J_, p. 40). (Publication not seen.) 

Type locality: presumably Novocomi (Italy?) 

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Size 2.5-5 mm. Color reddish-brown. Head with a prominent double 
tubercle over the base of the antenna and another prominent, single 
tubercle over the eye; thorax widest in front, lateral margins nearly 
straight, anterior and posterior angles acute, pronotum very coarsely 
and densely punctate, punctures confluent, Y-shaped impression on the 
disc, the arms of the Y extending from the anterior margin of the 
pronotum, at the point where the lateral margins of the head meet the 
prothorax, to the center of the pronotum, and the base of the Y extending 
nearly to the posterior margin of the pronotum; elytral pubescence con- 
fused, short, sparse, recumbent, fine, yellow in color; punctures on 
elytra confused, shallow, moderately dense, elytra with variable, vague 

This species is included in Kraus's key (4). 

Hosts : Licorice root, dried roots, chair, umbrella handle. 

Distribution and interceptions : "Central Europe, Syria, Barbary 
Coast /AfricJ7 " (Lesne ]_, p. 15); Turkey (via New York, N. Y.); France 
(via New York, N. Y. ); Mississippi (Hopkins, in Kraus 4_, p. 130; speci- 
men in U. S. National Museum collection). 

Lyctus villosa Lesne 

Lyctus villosus Lesne (6^, p. 537). 

Type locality : Mexico: Zacoalco (Jalisco). 

Size 2-3.5 mm. Color reddish-brown. Entire body covered with 
long, coarse, almost scalelike, semierect hairs which are broadened 
apically; head without tubercles; thorax quadrate, sides parallel, but 
slightly sinuate, anterior and posterior angles rounded, surface of 
pronotum coarsely rugose-punctate, punctures confluent; elytra with 
pubescence arranged in even, double rows, punctures in serial arrange- 
ment between rows of pubescence. 

This species will key to Lyctus linearis Goeze in Kraus's key 
(_4, p. 120). L. villosa is separated from _L_. linearis by the coarse, 
scalelike pubescence, which is fine and appressed in the latter species. 

Hosts: Unidentified wood, furniture, cedar closet, medicinal herbs, 
"Banak" wood, balsa wood, on banana, wood ceiling in house, woodwork 
in church, oak flooring, cigar boxes, in Leucaena esculenta (Moc. and 
Sesse) Benth. (Leguminosae). 

Distribution and interceptions: Mexico: Zacoalco, Guadalajara 
(Jalisco) (via Nogales, Ariz.), "Mexico" (via Binghamton, N. Y.), 
Monterrey(via Laredo, Tex.), "Mexico" (via Laredo, Tex.), Mexico, D.F. 


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3 1262 09239 6380 

Tepic, Nayarit (via Nogales, Ariz.); San Salvador: San Salvador; Costa 
Rica: "Costa Rica" (via New York, N. Y.); Panama: "Panama" (via New 
Orleans, La.); Dutch Guiana: "Dutch Guiana" (via Tampa, Fla., and 
New York, N. Y.); Ecuador: "Ecuador" (via Tampa, Fla.); United States: 
Redlands, Calif., Clemson College, S. C, Brooklyn, N. Y., Tucson, 

Literature Cited 

(1) Comolli, A. 

1837. De Coleopteris novis ac rarioribus minusve cognitis 

provinciae Novocomi. 54 pp. Ticini, Fusi. /_Publication 
not seen7 

(2) Fabricius, J. 

1792. Entomologia systematica, v. 1, 538 pp. 

(3) Gorham, H. S. • 

1883. Malacodermata. Biologia Centrali-Americana. Insecta, 
Coleoptera. v. 3, pt. 2, 372 pp. i3 pi. 

(4) Kraus, E. J. 

1911. A revision of the powder-post beetles of the family Lyctidae 
of the United States and Europe. U.S. Dept. Agr. Bur. 
Ent. Tech. Ser. No. 20, pt. 3, pp. 111-138. Includes 
appendix by A. D. Hopkins, Notes on habits and distri- 
bution with list of described species. 

(5) LeConte, J. L. 

1862. Classification of the Coleoptera of North America, Part I, 
Smithsn. Inst. Misc. Collect., v. 26, 286 pp. 

(6) Lesne, M. P. 

1911. Notes sur les Coleopteres Terediles. /Paris/ Mus. Natl. 
d'Hist. Nat. Bul.^ v. 17, pp. 534-538, 


1938. Bostrychidae. Coleopterorum Catalogus. Pars 161, 84 pp. 

(8) Melsheimer, F. E. 

1846. Descriptions of new species of Coleoptera of the United 
States. Acad. Nat. Sci. Phila. Proc. 2, pp. 98-118.